A washer apparatus suitably used for automobile is required to wipe a large area with a small quantity of washer fluid in a short time. On this account, spread (spray)-type jet nozzles which are capable of jetting washer fluid over a large area to increase wiped areas have been proposed (e.g. Japanese Unexamined Patent Application Publication No. 2002-67887).
In this type of washer nozzle, a nozzle chip is built in a nozzle body and further the nozzle chip has an oscillation chamber for self-oscillating the pumped washer fluid. In the oscillation chamber, a channel of washer fluid fed through a feed passage in the nozzle body is formed (main channel). In addition, a plurality of feedback channel is formed therein for branching, guiding, and returning part of the washer fluid to the main channel. Thus, the washer fluid guided by the feedback channels provides a control flow, which in turn causes the washer fluid flowing through the main channel to self-oscillate. Then, the self-oscillating washer fluid is jetted in a fan-shaped spread flow over a large area.
However, if the washer fluid is spread and jetted over a large area using such a spread-type jet nozzle, the distribution of the quantity of the jetted washer fluid is not uniform. The quantity of fluid is high at both the ends of the fan-shaped spread flow and low in the center. If the washer fluid supplied onto a windshield glass is expected to spread by wiper blades, it is required to perform wiping operation more than once. Therefore, the washer fluid is not quickly spread and some areas can be remained unwashed, especially, when muddy water is sticking to the windshield glass. Further, in such a spread-type jet nozzle, the particle size of jetted washer fluid is relatively small. Therefore, the jetted washer fluid is easily affected by the airflow when the vehicle is driving at high speed, and a splashdown of the washer fluid falls down from a target point. As a result, the washer fluid is not supplied to the upper part of a windshield glass and a large unwashed area remains. Accordingly, it is difficult to secure a sufficient field of view at the driver's side.
The particle size of washer fluid is relatively small, as mentioned above. Therefore, if the spread angle of spread jet is increased so as to increase the wiped area, part of jetted fluid is flown by the airflow and sprayed out of the windshield glass. As a result, the jetted fluid is not effectively utilized.
The present invention is made with the above-mentioned problem taken into account. The object of the present invention is to provide a washer nozzle and a washer apparatus which are capable of spraying and supplying washer fluid even to areas which are likely to remain unwashed by a wiper apparatus so that wide fields of view for the driver and front-seat passenger are secured quickly and stably.